A speed cushion is a raised road hump that extends only part-way across the carriageway width, leaving gaps alongside each kerb. These gaps allow larger vehicles — buses, ambulances, fire engines — to straddle the cushion and pass unimpeded, while cars are forced to drive over it, reducing their speed. Speed cushions are defined in the Highways (Road Humps) Regulations 1999.
What is a Speed Cushion? — Complete UK Guide
Speed cushions are a sophisticated evolution of the traditional speed bump — designed specifically to solve a problem that plagued earlier traffic calming schemes: how do you slow car traffic without impeding buses, ambulances and fire engines? The answer is the speed cushion, whose narrower width (typically 0.9m to 1.0m per cushion element) fits exactly within the wheelbase width of a passenger car, while being much narrower than the wider wheelbase of a bus, coach or large emergency vehicle.
How Speed Cushions Work
A speed cushion installation typically consists of two (or sometimes three) individual cushion elements placed side by side across the carriageway, with gaps between them and between the outer cushions and the kerb. The gaps are designed to correspond to the wider wheelbase of buses, coaches and HGVs, allowing these vehicles to position their wheels in the gaps and drive through without significant discomfort or vehicle damage. Car drivers, whose narrower wheelbase means their wheels land on the cushion elements, experience a speed reduction — the vertical displacement encourages them to slow down to 20–25mph to avoid a jarring impact.
Speed cushions are particularly valued on bus routes, where full-width speed humps would slow buses and reduce service reliability. The same logic applies to ambulance and fire service routes — studies have shown that full-width speed humps can significantly delay emergency response times, and speed cushions minimise this delay while maintaining traffic calming effectiveness for general traffic.
Speed Cushions vs Speed Bumps vs Speed Humps
These terms are often used interchangeably but they refer to distinct products in the UK:
- Speed bump — a short, raised hump, typically 25mm–100mm high and 300mm–600mm long (in the direction of traffic), extending the full width of the carriageway. The short length causes a sharp jolt at all speeds. Often used in car parks and private roads where low speeds (under 10mph) are required.
- Speed hump — a longer, raised hump than a speed bump, typically 3.7m–10m long in the direction of traffic (for road humps on public roads). The extended length causes a more gradual rise-and-fall experience compared to a speed bump. The Highways (Road Humps) Regulations 1999 define legal road humps (for public roads) with specific minimum length requirements to prevent the jarring effect of shorter speed bumps.
- Speed cushion — as described above: a width-selective hump that allows large vehicles to straddle it. Typically used on bus routes and emergency vehicle corridors.
- Speed table — a flat-topped hump, essentially a raised platform across the full carriageway width. Often used at pedestrian crossings to create a raised crossing point (combining traffic calming with a safe pedestrian space).
UK Regulations for Speed Cushions
Speed cushions on public roads in England and Wales are governed by the Highways (Road Humps) Regulations 1999. Key requirements include:
- The overall horizontal dimension (in the direction of travel) must be between 0.9m and 6.5m
- The height must not exceed 100mm on roads with a speed limit of 20mph or less, and not exceed 75mm on roads with higher speed limits
- They must be accompanied by prescribed approach and departure warning signs
- They should be lit in accordance with the Regulations where the road is lit
- A Traffic Regulation Order (TRO) is required for installation on a public road, made by the relevant highway authority
On private roads and private land, these regulations do not apply — rubber speed cushions can be installed without a TRO or planning permission.
Speed Cushion Applications in the UK
Bus Route Traffic Calming
Speed cushions are the preferred traffic calming measure for routes served by buses, where maintaining journey time reliability is important. London's extensive bus network, and many urban bus routes across major UK cities, uses speed cushions rather than full-width humps to allow buses to maintain momentum.
Emergency Vehicle Routes
Any traffic calming scheme close to a hospital, fire station or on an ambulance response route should use speed cushions rather than full-width humps, to minimise delays to blue-light vehicles. UK ambulance services formally object to the installation of full-width road humps on ambulance response routes.
Residential Roads with Mixed Traffic
Speed cushions are suitable for residential roads where a mix of car and larger vehicle traffic (delivery vans, refuse trucks) makes width-selective calming desirable.
Speed Cushion Materials and Costs
Speed cushions are available in rubber (recycled or virgin), asphalt and pre-formed polymer. For private road and car park applications, bolt-down rubber speed cushions are widely available — typically 100mm high, 900mm wide, 500mm long, in black or black-and-yellow finish. Costs for rubber speed cushions on private land: approximately £180–£350 per cushion element for supply and installation, depending on size and quantities.
Buy Speed Cushions from Barriers Co
Barriers Co supplies rubber speed cushions for private road and car park applications across the UK. Available in 500mm, 750mm and 1000mm lengths, in black and yellow or solid black finish, with stainless steel fixing bolts. Fast UK-wide delivery. Contact us for a free quote and volume pricing.